1. Field of the Invention
The present invention relates to an apparatus and method for confirming proper endotracheal tube placement.
More particularly, the present invention relates to an apparatus and method for confirming proper endotracheal tube placement, where the apparatus includes a microphone and an audio signal receiver and output unit capable of receiving sound produced by squeezing a pilot balloon of the endotracheal tube filled with a mixture of a gas (such as air) and a liquid (such as water) and the method includes placing the microphone on a suprasternal notch of a patient, inserting the endotracheal tube, filling the pilot balloon with a mixture of a gas and a liquid, squeezing the balloon and analyzing the sound generated by the balloon in a digital sound acquisition and localization unit to confirm proper endotracheal tube placement.
2. Description of the Related Art
The most important job an anesthesiologist does is to place an endotracheal tube (ET) in the trachea when general anesthesia with a secure airway is indicated. The inability to place the ET in the trachea or to misplace the ET in the esophagus can lead to disastrous results and even death. The ET has a pilot balloon that communicates with the cuff on the endotracheal tube. When the pilot balloon is inflated with air/gas, it inflates the endotracheal tube cuff. This produces a seal so the chances of gastric contents entering the trachea are minimized. The endotracheal tube cuff can be felt in the suprasternal notch when the pilot balloon is compressed. Presently there are three ways to confirm proper placement of the endotracheal tube: (1) water vapor mist in the endotracheal tube; (2) auscultation of bilateral breath sounds when oxygen or air is deliver through a reservoir bag or Ambu bag; and (3) detection of carbon dioxide either on a capnograph or a disposable CO2 monitor, which is today considered the gold standard by the American Association of Anesthesiologists. But none of these methods are 100% confirmatory.
United States Published Patent Application No. 20030018276 discloses a system and method for use in detecting an endotracheal tube location within a body electronically detects indigenous breath sounds emanating from a region of the body and processes the detected indigenous breath sounds to generate a parameter representative of an acoustic characteristic of the body associated with the endotracheal tube location within the body. The system and method generates an output indicative of the endotracheal tube location within the body based on the parameter representative of the acoustic characteristic of the body. The system uses a speaker to generate an input signal that is then detected by an microphone or other audio detector.
U.S. Pat. No. 6,349,720 disclosed an endotracheal tube having an audio aid for indicating the accurate placement thereof. In a first preferred embodiment, the invention comprises a cuffed ETT having distal and proximal ends, the latter having a mechanical noise-making apparatus formed thereon that provides an audible signal when air passes therethrough. In a second preferred embodiment, the invention comprises the combination of a cuffed ETT having distal and proximal ends and an insertion rod for stiffening the ETT during insertion. The insertion rod is coupled to an electrically-powered noise maker formed upon the distal end thereof to produce an audible sound before air flow through the ETT is established. In both embodiments the correct placement is determined by the unaided ear hearing the noise coming from both sides of the chest. If sound is from one side only the insertion is too deep. If the sound is heard from the stomach the ETT is in the esophagus instead of trachea and should be pulled out and reinserted.
U.S. Pat. No. 5,445,144 disclosed an apparatus and method for acoustically guiding a distal end of a tube within a body. The apparatus and method generates an incident sound pulse in the tube which propagates into the body, detects sound pulses resulting from the incident sound pulse and from reflected sound pulses from within the body, and processes the detected sound pulses to guide insertion of the distal end of the tube within the body. The apparatus and method provides an indication of the position of the distal end of the tube within the body conduit, estimates dimensions of the body conduit adjacent the distal end of the tube, and determines if the tube is obstructed.
Although these methods and their associated apparatus are known, there is still an need in the art for apparatuses and methods that improve the ability to confirm proper ET placement.